Physical, chemical, and biological properties of the soils used in this study.

<p># Total soil organic carbon (OC); total soil nitrogen (TN); the ratio of OC to TN (C/N); exchangeable potassium (K); dissolved organic carbon (DOC); total dissolved nitrogen (TDN); the ratio of fulvic acid to organic carbon (FA); the ratio of humic acid to organic carbon (HA); total phospholipid fatty acids (PLFA-T); fungus phospholipid fatty acids (PLFA-F); actinomyces phospholipid fatty acids (PLFA-A); bacteria phospholipid fatty acids (PLFA-B); Gram-negative bacteria phospholipid fatty acids (PLFA-G^-); Gram-positive bacteria phospholipid fatty acids (PLFA-G⁻); the ratio of PLFA-G⁻ to PLFA−G⁺ (G⁻/G⁺);